Plug and switch box



April 2, 1946. D. CCIDNLAN 2,397,595

PLUG AND SWITCH Box Filed July 2, 1943' 2 Sheets-Sheet 2 Patented Apr. 2, 1946 UNITED STATES PATENT OFFICE PLUG AND SWITCH BOX David Conlan, Brooklyn, N. "2., assignor to Conlan Electric Corporation, New York, N. Y.

3 Claims.

The invention herein disclosed relates to apparatus for providing the extension circuits used on board ship.

Objects of the invention are to provide a watertight form of outlet box and plug construction, which will be so protected that the plug can not be inserted into the receptacle when the current is on and in which it will be assured that the receptacle contacts are dead when there is no plug in the box.

Another important object of the invention is to enable control of the extension plug circuit without having to pull the plug out of its receptacle.

Further objects are to provide a sturdy watertight form or construction having the foregoing advantages, which will be practical and reliable in every way. Other desirable objects will appear as the specification proceeds.

The drawings accompanying and forming part of the specification illustrate present commercial embodiments of the invention, but it should be understood that structure may be modified and changed as regards the immediate disclosure all within the true intent and broad scope of the invention as hereinafter defined and claimed.

Fig. 1 is a longitudinal sectional view of a form of the invention employing a rotary type switch and showing the parts with the plug in place and the switch in the open circuit position.

Fig. 2 is a cross-sectional view of the plug and receptacle parts of the combination, as on substantially the plane of line 2-2 of Fig. i.

Fig. 3 isa broken longitudinal sectional view of the receptacle end portion of the box with the plug removed and the switch locked in the off position.

Fig. 4 is a plan view of the box with cover removed and the plug in position'and shown in section, this view appearing as on substantially the plane or" line l4 of Fig. 1.

Fig. 5 is a side and broken sectional view of a modification, embodying a switch of the oscillating or toggle form of construction.

Fig. 6 is a broken sectional detail on substantially the line 5-6 of Fig. 5.

The box structure is shown as comprising a box body 7, constructed for mounting on a wall, ceiling, deck. or other support and provided with a watertight cover 8, having 'a flanged opening at 9, ior the plug H), of the extension circuit cable l As shown in Figs. 1 and 2, the plugmay be secured in wateitight relation by a screw flange 12, engaged with the cover flange 9.

. switch 55, with conductors f9, 20, extending to the receptacle contacts l5, l6.

The box is shown as having a transverse partition 2%, separating the interior of the same into a compartment for the switch and a separate compartment for the plug receptacle. This partition is shown as having'an archway 22, at the foot of the same to pass the wiresto the receptacle compartment and the base 23, of thereceptacle is shown as hollowed at the: underside to accommodate such wiring and as shaped to closely fit the bottom of the box and over the archway, and provided with a gasket 241 This construction keeps the switch compartment sealed off in watertight relation from the receptacle compartment.

To assure the receptacle contacts being dead when the plug is out of the box, means are pro vided for securing the switch in the open circuit position when the plug is removed. This same means, in the first form of' the invention, also isutilized to lock the plug in position when the circuit is closed.

The mechanism for such purposes is shown as comprising a cam 25, fixed on the switch spindle 26, and arranged on the one hand to project a locking bolt 27, into an opening 28, in the side of: the plug body or On the other hand, to be held against turning by said bolt when the-latter is secured in the retracted position shown in Fig. 3, by a holdback pin 29', releasable only by insertion of the plug.

The locking bolt 21, is shown as slidingly guided through the upper part of the partition at 30, and as pressed by spring 3!; against'the periphery of the switch cam 25. The'latter is indicated in Fig. l, as having high portions 32, which will pro- .iect the bolt and hold it locked into the plug, in the closed circuit position of the switch and with depressions 53. which will permit retraction of th bolt free of the plug and also preventthe'cam turning when the bolt is locked in the inner position, Fig. 3. These recesses or locking portions of the cam are shown as each having a gradual rise at one side at 34, faced in the direction of rotation of the switch and leading up to the high portion 32, to smoothly project the bolt.

The bolt locking pin 29, is shown as sliding in a guide 35, up through the bottom of the receptacle base and as connected by a bar 36, across the bottom with a plunger 31, projecting up through a guide 38, in position between the re ceptacle contacts and in line with a pin 39, on the end of the plug. This pin is shown set back in a cavity 40, in the end of the plug, of a size to freely receive the projecting guide bushing 38, surrounding the plunger 31.

The stationary upstanding guide bushing 38, serves as a guard to prevent the plunger 31, being pushed back by an inserted finger, screw driver or other implement and further requires that only a plug intended for the receptacle be used because such plug must have the cavity 49, to fit over this guard and a central pin 39, of a proper size and length to enter the guard and push back the plunger far enough to lower the pin 29, from in front of the locking bolt; 21.

The U-shaped member made up of the bolt securing pin 29, and the connected releasing plunger 31, is pressed upward into the retaining position in the illustration, by a spring 4|, within the hollow of the receptacle base acting upward against the connecting strap 36.

The means for turning the switch consists in the illustration of a knob 42, rotatably mounted on the box cover and having drive lugs 43, Fig. 4. entering seats 44, provided in the top of the cam.

With the construction described, the switch may be operated at will, while the plu is seated in the box, to turn the current on or oil to the receptacle contacts and thus to control the extension circuit. When the current is on however, the bolt 21, will be pr jected into lockin gagement with the plug and hence the plug can not be withdrawn when the receptacle contacts are alive. Therefore, to remove the plug, the switch must first be thrown to out 01f current to the plug contacts. When this is done, the plug is free to be withdrawn but, as the plug is removed, the retainer 29, will then rise as in Fig. 3, to block the bolt 21. In this blocked condition, the bolt holds the cam against turning and hence th switch can not be rotated to close the circuit when the plug is out of the box. The switch then can only be operated by inserting a proper plug which, as described, is designed in the nature of a key, to enter the receptacle and to force back the retainer which holds the switch and plug lockin bolt. Then when such a plug is in place, the switch may be turned to turn the current on to the receptacle and by this act, the plug becomes locked in place.

In that form of the invention shown in Figs. 5 and 6, a toggle switch 45, is employed in place of a rotary switch and actuation of this switch in the circuit closing direction is effected by and under control of the plug.

The actuating rocker 49, of the toggle switch is shown biased in the circuit opening direction by a spring 41, and as operated in the circuit closing direction by a plunger 48, adapted to be projected by a key pin 49, in the end of the plug.

The plunger 48, is shown as operating in a tubular guid 50, extending through the receptacle base 5|, which in this instance, serves as the cross partition in the box and this guide is shown as having attached to it a guard sleeve 52, which may be of insulating material. The plug, as in the first construction, is formed with an end cavity 53, to receive the guard tube 52.

A spring 54, within the guide 50, serves to hold .the plunger 48, in retracted relation with the switch retained in open circuit condition by spring 41, when there is no plug in the box.

When th special plug designed for the box is inserted as in Fig. 5, the plunger 48, will be proiected and caused to rock the switch into the circuit closed position for extending current to the receptacle contacts l5, It. In this construction, the plug is free to be removed at any time and when it is removed, permits the switch to swing to the open circuit condition, with the receptacle contacts deenergized.

To enable control of the extension plug circuit while the plug is in place, the box is provided in this form of the invention with an exposed push button 56, on a plunger 51, operating through the box wall and carrying a cam 58, sliding through a slot 53, in the tubular portion 68, of the switch handle and through a slot 6|, in the plunger portion 62, of that handle, to thrust back the latter clear of the operating plunger 48. The part 62, is pressed outward in the tubular portion 83, by spring 63, so as to normally overstand the end of plunger 48, and be engaged thereby to close the switch when the plug is inserted, but at any time after that, the push button may be operated-to telescope the handle inwardly free of the plunger, whereupon the spring 41, will snap the switch to open circuit condition and thus cut off the receptacle contacts. Then, if it be desired to again close the plug circuit, the push button plunger may be pulled outward, whereupon the cross pin 64, in the lower end of the wedge will pick up the tubular switch handle and bring the switch back to the closed circuit position.

The spring 63 is strong enough to hold the sliding portion 62, of the switch handle pushed outward against the cam, when the plug is inserted, thus to automatically project the push button into position, where it may be utilized for interrupting the plug circuit and spring 41, is strong enough to pull the switch to open circuit position whenever the plug is removed.

The push button plunger is shown operating through a watertight gland 65, and similar watertight connections may be provided where the switch actuating plunger 48, operates through the insulating partition 5|, Fig. 5, and where the locking bolt 21, Fig. 1, operates through partition 2|, and the plunger elements 29, 31 operate through the receptacle base 23.

The guard tube 38, in the first illustrated form of the invention and the similar guard tube 53, in the Fig. 5 form of the invention, may be of insulating material. These tubes may be screwed into the bases 23 and 5|, respectively, so that if need be, they could be removed by an authorized person to permit use of an ordinary form of plug in the receptacle. In such a case, the plunger 31, Fig. 3, or plunger 48, in Fig. 5, might be a Bakelite rod or other insulating material.

To make a watertight joint when the plug is removed in the Fig. 5 construction, the head 6'6 of the switch actuating plunger 48, may carry or may engage a gasket 61, to provide close sealed engagement with the flange 68, in the end of the guard tube 53.

What is claimed is:

l. A combined plug and switch box, comprising a watertight box having switch and receptacle compartments, a rotary switch in the switch compartment having an exposed operating handle, a plug receptacle in the receptacle compartment, said box having an opening to said receptacle for entry of a plug, a plug cooperable with said receptacle, a movable trip engageable and operable by said plug when the latter is inserted in the receptacle, a plunger extendin from said switch compartment into said receptacle compartment and positioned to be stopped by said trip when the latter is not forced back by said plug, a member carried by the rotary switch in line with said plunger and having one or more recesses to receive and be thereby held by said plunger against rotary movement when said plunger is stopepd by said trip and said member being arranged on operation of the switch to project said plunger into holding engagement with said plug, when said trip is forced back by insertion of the plug in the receptacle.

2. A combined plug and switch box, comprising a watertight box having a plug opening, a plug receptacle in the box in line with said opening, a plug 1 or engagement with said receptacle, a plunger in said box in line with the movement of plug entry, a guard of insulating material about said plunger, said plug having an opening in the end of the same to receive said guard and provided with a pin within said opening positioned to engage and actuate said plunger, a switch mounted in the box and connected to control said plug receptacle, a rotary cam operable by said switch, a locking bolt positioned to be projected by said cam when the switch is turned on and to be retracted when the switch is turned on, the plug having an opening in the side of the same to receive the end of said locking bolt when projected and a holdback pin connected with said plunger and disposed to prevent projection of the locking bolt when the plug is not in position in the receptacle and to be displaced from such holdback position when the plug is inserted in the receptacle.

3. A combined plug and switch box comprising a support, a plug receptacle and a rotary switch mounted in spaced relation on said support, a plug engageable with said receptacle, a cam operated by said rotary switch, a locking bolt slidably mounted on the support and extending from said cam toward said plug in its seated position in the receptacle, a spring yieldingly holding said locking bolt in engagement at one end with said cam, said cam having a locking recess into which said bolt end may engage to secure the cam and the switch against operation and said cam further having a cam surface for projecting the sliding bolt toward the plug, said plug having a locking shoulder engageable by the bolt when the latter is projected by said cam surface, a spring projected stop positioned to hold the locking bolt back in retracted position engaged in said looking recess and means connected with said stop and positioned in the path of entry of the plug into the receptacle for eifecting the shifting of said spring projected stop out of holding relation with said locking bolt upon insertion of the plug into the receptacle.

DAVID CONLAN. 

